The present invention relates to a yarn winding apparatus or takeup machine for winding a plurality of continuously advancing yarns into yarn packages.
Takeup machines of the described type are used in spinning lines for winding freshly spun multifilament yarns to packages. To this end, a plurality of bobbin tubes are inserted one after the other on a winding spindle mounted in cantilever fashion, and they are each uniformly wound with a yarn. In this process, as many as ten packages are wound side by side on the winding spindle at the same time, so that the winding spindle has a projecting length of more than one meter.
To realize high yarn speeds of more than 6,000 m/min., the winding spindle must operate, depending on the diameter of the packages, from the beginning to the end of the winding to a package (winding cycle) in a speed range from about 2,000 rpm to 30,000 rpm. In this connection, it is necessary to avoid in particular critical speeds which cause an undamped vibration of the winding spindle, so as not to destroy the unilateral mount of the winding spindle. A critical speed is present, when the frequency of excitation coincides with the inherent frequency of the winding spindle. Based on the wide speed range and the fact that the rotating masses constantly change during the winding cycle and thus influence the critical speeds, such critical speeds may occur. In addition, in particular at the end of a winding cycle, the winding spindle is subjected by the wound packages to a considerable dead weight, which causes the winding spindle to bend.
DE 195 34 914 discloses a takeup machine, wherein a holding device is mounted at the free end of the winding spindle. The holding device comprises a receptacle for engaging the free end of the winding spindle, so that the winding spindle receives a supporting mount at its free end. This holding device is made pivotal, so as to enable a movement of a spindle support that guides the winding spindle. To this end, the spindle support and the holding device are driven. For doffing the packages a gripping device is provided, which disengages the winding spindles from the holding device and removes same from the spindle support. This takeup machine requires a considerable mechanical complexity that is difficult to manage. Furthermore, the drive of the holding device and the drive of the spindle support must be totally synchronous, so that there is no delay on the winding spindle.
A very similar takeup apparatus is disclosed in U.S. Pat. No. 5,234,173. In this apparatus, the gripping device that disengages the winding spindle for doffing the package may be omitted, since the holding device is constructed for such a swinging movement that the winding spindle is released for doffing the full packages. However, the known takeup apparatus has the disadvantage that for purposes of performing a rotation and a swinging movement, the holding device requires a very complex construction, which exhibits in particular an inadequate stability for absorbing vibrations of the winding spindle.
U.S. Pat. No. 4,304,364 discloses a further takeup machine, wherein during the winding cycle a holding device is mounted at the free end of the winding spindle. This holding device has a cone that cooperates in formfitting manner at the free end of the winding spindle with a cone in the winding spindle. The holding device is constructed for swinging movement, so as to be able to doff packages on the winding spindle. In this takeup machine, the winding spindle is stationarily mounted in the machine frame, so that a movement of the holding device is necessary only for purposes of stripping the winding spindles. However, even in this case, it is necessary to align the winding spindles in their unloaded state and the holding device very exactly, so as to enable an engagement without delaying the winding spindle.
DE 42 40 920 discloses a takeup machine, wherein two winding spindles are arranged on a rotatable spindle support and alternately rotated to a winding range and a doffing range by rotating the spindle support. For damping the vibration, a vibration absorber is arranged in the frame of the takeup machine. Such vibration absorbers show an optimal damping behavior only in a relatively narrowed frequency range. With that, however, it is not possible to damp the vibrations in the takeup machine over the entire speed range. On the contrary, the ranges of the critical speeds are shifted only in terms of frequency. In the extreme case, traversing the critical speeds may lead to a breakdown of the takeup machine.
It is therefore an object of the invention to further develop a yarn winding or takeup machine of the initially described type, so that the winding spindle can be engaged in a simple manner with a holding device which facilitates, irrespective of the movement of the spindle support, winding of a plurality of yarns in the entire operational speed range with a large distribution of the rotational speed.
A further object of the invention is to provide a yarn winding or takeup machine which can be used in particular in the low speed range with a high dead weight of the winding spindle with a winding spindle longer than one meter.